Depth of Knowledge
Webb developed four DOK levels that grow in cognitive complexity and provide educators a lens on creating more cognitively engaging and challenging tasks. Webb's Depth of Knowledge (DOK) provides a vocabulary and a frame of reference when thinking about our students and how they engage with the content.

Read the article "Depth of Knowledge Levels for Four Content Areas" by Norman Webb. Using the Cognitive Reasoning Matrix and the article to develop and understanding of "rigor."
from http://schools.nyc.gov/